Decrypt PGP encrypted file with passphrase only in

Question

I have a PGP file named 'filename.txt.pgp' that I need to decrypt. When I run decryption from command-line it asks me only for the password. I use gpg command:

gpg filename.txt.pgp

The password is enough and my file is decrypted. I can read it's content.

Now, I should create an utility in Java. After research I see that Bouncy Castle library is my best choice. But all the examples in Java I can find use public/private key file which I do not have.

Could you please help me with an example in Java that decrypts PGP file using just a password?

Thank you.

Answer 1

If you look at the documentation section of Bouncy Castle's site, they say to "...look at the test programs in the packages..." and they're not joking.

If you look inside the jar file from Bouncy Castle you will see under the \org.bouncycastle\openpgp\examples\ directory a class file called "PBEFileProcessor" that will cover password based encryption when using their library.

Here's a link to the same file in their Github repo.